Photographic processes and products



June 7, 1966 E. H. LAND PHOTOGRAPHIC PROCESSES AND PRODUCTS 5 Sheets-Sheet 1 Filed July 24, 1962 ATTO RNEYS June 7, 1966 Filed July 24, 1962 E. H. LAND PHOTOGRAPHIC PROCESSES AND PRODUCTS 5 Sheets-Sheet 2 FIG 4 5 i123:-

' BY MUM Gnu-L ATTO RNEYS June 7, 1966 E. H. LAND 3,255,009

PHOTOGRAPHIG PROCESSES AND PRODUCTS Filed July 24, 1962 5 Sheets-Sheet 5 IN V TOR. fig;

ATTORNEYS United States Patent 3,255,009 PHOTQGRAPHIC PROCESSES AND PRODUCTS Edwin H. Land, Cambridge, Mass, assignor to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware Filed July 24, 1962, Ser. No. 212,072 3 Claims. (Cl. 661) This application is a continuation-in-part of application Serial No. 647,675, filed March 21, 1957, now US. Patent 3,120,795.

The present invention relates to photographic processes and products useful therein and, more particularly, to processes and products for treating an exposed silver halide emulsion in a novel manner.

The primary object of the present invention is to produce satisfactory negatives of usable density with unusual speed and ease.

Another object of the invention is to provide an monobath which both develops and fixes to permit rapid and eflicient processing of a plurality of interconnected exposed siliver halide emulsions.

Still another object of the invention is to provide a rapid and efficient process of developing a plurality of exposed silver halide emulsions to prepare photographic negatives of suflicient density to produce one or a plurality of positive images therefrom by conventional photographic printing processes at some time subsequent to the formation of the said photographic negative.

Yet another object is to provide, as a novel product, a container particularly adaptable to the practice of the novel processes of this invention.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such. steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fullerunderstanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

FIGURE 1 is a perspective view, partly broken away, of the container of a product incorporating the present invention;

FIG. 2 is a cross-sectional view of the container of FIGURE 1, taken substantially along the line 22;

FIG. 3 is a cross-sectional view of the container FIG. 1, taken substantially along the line 3-3;

FIG. 4 is a cross-sectional view of the container FIG. 1, taken substantially along the line 4-4;

FIG. 5 is a perspective view, partly broken away, of the container of another product embodying the present invention; and

FIG. 6 is a perspective view of the container of FIG. 5 in operation.

In US. Patent No. 2,662,822, issued to Edwin H. Land on December 15, 1953, novel photographic compositions for obtaining photographic images by diffusion transfer are described and claimed. As disclosed in the aforementioned patent, these compositions may include an external phase and an internal phase. The external phase contains a silver halide developer that acts throughout the emulsion to reduce exposed silver halide to silver, and a silver halide solvent that acts throughout the emulsion to react with a unreduced silver halide to form a soluble complex silver salt. The internal phase contains solid particles that serve as precipitation nuclei at which dely precludes its return to the negative.

Patented. June 7, 1966 velopment of the complex salt to silver occurs at a rate that for the most part precludes its return to the print being produced. The developing composition is preferably confined in a frangible container which is ruptured at some time subsequent to photoexposure to permit spreadingof the developing composition uniformly between the exposed negative and a superposed imagecarrying layer. In this manner, a transfer image of excellent contrast and density is obtained, while the negative is of low density and, according to the process taught in the patent, would normally be discarded after separation from the image-receiving layer.

It has now been found that developing compositions of the foregoing description are particularly useful in a onestep process for developing an exposed silver halide emulsion to produce an excellent negative of good density which may be employed at some time subsequent to development to prepare one or more positive images by conventional procedures well known to those skilled in the art. The present invention is particularly useful in the development of a plurality of interconnected exposed emulsions to provide a rapid and eflicient one-step process for producing a plurality of visible records substantially simultaneously. As used herein and in the appended claims, the term plurality of interconnected exposed emulsions is intended to include a single light-sensitive emulsion layer containing a plurality of exposed frames, as Well as a plurality of light-sensitive emulsion layers interconnected in a continuous strip having areas separating the respective emulsions, which areas are not lightsensitive.

From the foregoing discussion, it will be apparent that the present invention encompasses developing processes useful in both still and motion-picture photography.

According to the practice of this invention, an exposed silver halide emulsion, e.g., a silver halide emulsion which has been subjected to photoexposure through a lens in any suitable way, or a plurality of interconnected exposed emulsions, is immersed in a fluid suspension having an external phase containing an aqueous alkaline solution of a silver halide. developer and a silver halide solvent, and an internal phase containing suspended solid particles. The developer and the solvent act throughout the silver halide stratum to reduce exposed silver halide to silver and to react with unreduced silver halide to form a soluble complex silver salt. The solid particles serve as precipitation nuclei, at which deevlopment of the complex salt to silver occurs at a rate that substantial- The solid particles are maintained in suspension by any suitable dissolved, synthetic or other dispersing agent. The quantity of fluid is great enough to be substantially maintained at a predetermined magnitude, notwithstanding the absorption of relatively minute proportions of its external phase by the latent images processed thereby. Preferably the fluid suspension is agitated while the silver halide stratum is immersed therein in order to ensure free circulation of the developer and the solvent between the latent image and the dispersed solid particles. During the processing period of the antihalation layer, with which the supported silver halide emulsion usually is provided, either bleaches or dissolves. A particularly convenient way of subjecting successive images to the fluid suspension described above is to insert the emulsion bearing the latent image or images through a fluid-retaining squeegee into a container carrying the fluid and, at the end of a predetermined processing period, to withdraw the emulsion bearing the finished negative or negatives from the container through the aforementioned squeegee or another one.

In one form, the external phase of the fluid is an aque- I ous alkaline solution of a silver halide developer and a silver halide solvent. Suitable developers are: benzene derivatives having at least two hydroxyl and/or amino groups substituted in ortho or para position on the benzene nucleus, such as hydroquinone, amidol, metol, glycin, para-aminophenol and pyrogallol; and hydroxylamines, in particular, primary'and secondary aliphatic and aromatic N-substituted or ,B-hydroxylamines which are soluble in aqueous alkali, including hydroxylamine, N-methyl hydroxylamine, N-ethyl hydroxylamine, and others described in copending application Serial No. 470,802, filed November 23, 1954 in the name of Edwin H. Land et al., now Patent No. 2,857,276. Suitable silver halide solvents are; conventional fixing agents such as sodium thiosulfate, sodium thiocyanate, ammonium thiosulfate, and others described in Patent No. 2,543,181, isued to Edwin H. Land on February 27, 1951; and associations of cyclic imides and nitrogenous bases such as associations of barbiturates or uracils, and ammonia or amines, and other associations described in applications Serial No. 378,684, filed September 4, 1953.in the name of Edwin H. Land et al., now Patent No. 2,857,274.

In general, the internal phase comprises solid minute particles of a substance which is insoluble in the external phase and which accelerates the reduction, by the dc veloper, of such silver-bearing ions as are dissolved in the external phase. Substances most suitable for this pur pose are insoluble inorganic particles, particularly metallic sulfides and selenides, e.g., lead sulfide nickel sulfide, cobaltous sulfide, cupric sulfide, lead selenide and zinc selenide. Colloidal dispersions of metals such as silver and gold also are suitable for this purpose.

A wide range of polymeric materials may be dissolved in the fluid to maintain the internal phase and the external phase distinct. Examples of these polymeric materials are: vinyls such as polyvinyl alcohol; cellulosics such as methyl cellulose, ethyl cellulose, sodium carboxy methyl cellulose and cellulose acetate hydrogen phthalate; gums such as gum arabic; and proteins such as sodium alginate.

One form of silver halide stratum'incorporates one or more of the silver halides, of which silver chloride, silver bromide and silver iodide are examples, dispersed in a suitable protective colloid, for example, gelatine, agar, albumen, casein, collodion, a cellulosic such as carboxymethyl cellulose, a vinyl polymer such as polyvinyl alcohol or a linear polyamide such as polyhexamethylene adipamide. Examples of specific formulations of conventional emulsions suitable for such use are described in T. T. Baker, Photographic Emulsion Technique, American Photographic Publishing Company, Boston, 1948, chapter 4. This stratum is laminated to a support that may be composed of a suitable paper such as baryta paper, or a synthetic polymer such as nitrocellulose. When the support is composed of a polymer of the foregoing type, it is backed by an antihalation layer, which, for example, contains a dye that absorbs light actinic to the silver halide emulsion but which is decolorized or absorbed by the processing solution. Alternatively, the antihalation material capable of being bleached is incorporated in the support or between the support and the silver halide stratuin. Conventional dyes for these purposes include triphenyl methane dyes such as acid fuchsin'and malachite green, colloidal inorganic compounds such as colloidal manganese dioxide, and bleachable dyes such as indophenols and styryls.

Althoughthe developing suspension may be incorporated in any suitable container, the containers illustrated in the drawings are particularly adaptable to the practice of the novel process of the invention.

Ont container, useful in the process of the present invention, is shown in FIGS. 1 through 4 as comprising a generally flat open-topped parallelepiped shell 20. 'This container is more fully described and claimed in US. Patent No. 2,873,660. Container 20 comprises rectangulat side walls 22, 22 being slightly greater in extent than a single print 23 of several to be treated. These side walls are joined by relatively narrow end walls 24, 24 and a bottom wall 26. Walls 22, 22 and 24, 24 are provided at the open top of the container with outwardly directed flanges 28 (FIGS. 3 and 4) that impart strength and rigidity and that retain securely in position a flexible closure 30 to be described below. Preferably, container 20 is formed of a material, such as plastic, rubber or the like, having sufficient flexibility and resiliency to permit considerable recoverable deformation. Preferably, also, the material of the container is sufliciently transparent to permit visual observation of the level of liquid therein.

Closure 30, which covers the open top of the container, provides channels 32, angular in cross section, that re ceive flanges 28 at the free upper edges of walls 22, 22'

and 24, 24. Closure 30 is composed of a rubber-like material, such as natural rubber or neoprene, so that while being assembled on the open top of container 20, channels 32 may be deformed to receive and to securely grip flanges 28. As shown in FIGS. 3 and 4, closure 30 includes a plug portion within container 20 that provides inner depending side walls 34, 34 and end walls 36, 36 in fluid-tight engagement with the inner faces of side walls 22, 22 and end walls 24, 24 of container 20. In order to permit print 23 to be inserted into and removed from container 20, closure 30 is provided with a longitudinal slit 37 slightly greater in length than print 23 is in width. This slit, which is defined by inwardly directed lips 38, 38 of closure 30, is preformed so that these lips normally are held in the open position shown in FIG. 1.

Lips 38, 38 seal the open top of the container when pressed firmly against each other by a longitudinal channel-shaped clip 40. One end of clip 40 is pivoted at 42 to 9. lug 44 that integrally extends from the upper portion of an end wall 24 into the clip channel. When clip 40 is in open position so that lips 38, 38 are separated as shown in FIG. 1, latent image-bearing print 23 may be inserted between the lips into container 20 until its lower edge abuts against lower wall 26 of the container. Clip 40 has a medial slot 48 that receives the protruding edge of print 23 when pivoted into closed position. In this closed position, the clips depending legs 46, 46- confine the outer edges of closure 30. Under these conditions lips 38, 38 are pressed toward each other so as to provide a fluid-tight seal at the open top of the container. To ensure retention of clip 40 in closed position, legs 46, 46 are provided with inwardly directed beads 50, 50, which both grip portions of closure 30 that they contact and impart rigidity to the clip. The free end wall 52 of clip 40 is provided with an inwardly curved extension 54 that, when the clip is in closed position, embraces the associated end of closure 30 in order to secure clip 40 in closed position.

The inner corners of container 20 are provided with shoulders 56 which, by engaging the edges of print 23, prevent its image-bearing portions from being abraded by side walls 22, 22 of the container. The liquid in the container preferably is in sutlicient quantity to completely cover the image-bearing portions of print 23 when its lower edge is in contact with lower wall 26. At the end of a predetermined processing period, after it has been inserted into container 20, print 23 is withdrawn from between lips 38, 38 through slot 48 of clip 40 in substantially dry condition. This substantially dry condition results from removing the fluid from the surfaces of the print both by lips 38, 38 and by a plurality of interlacing squeegee elements 58, 60 and 6 2 which integrallly project slightly more than half way between the adjacent edges of walls 34, 34.

In theform shown in FIGS. 5 and 6, an alternative container, useful in accordance with the present invention, comprises an elongated open topped housing 68. Housing 68 comprises rectangular sidewalls 70, 70 slightly greater in height than a strip 72 (FIG. 6) of latent images to be treated is in width. Side walls 70, 70 are joined by a bottom wall 74 and-end walls 76 and 77 providing openings 80 and 82 that communicates with the housings open top. Housing 68 preferably is formed of a rigid material such .as a stainless metal or an alkali-resistant plastic. At the top of the housing is a closure 84 hinged at 86 and '88. Closure 84 is adapted to be locked in registration with the upper edges of side walls 70, 70 and end walls 76, 771by means of a toggle clamp 90, 92.

Two pairs of squeegees 94, 96 and 98, 100 define fluid-tight slits 102, 104 through which a film may be introduced to and removed from housing 68. These Squeegees, which in conventional fashion are composed of a rubber or rubberlike material, are held in position between retainers .106, 106 and 107, i107 and between retainers 108, 108 and end wall 77. These pairs of Squeegees resiliently press against a leader 109 and each other to provide a barrier which substantially prevents escape of 'the rfluid from within the container. A pair of moistureabsorbent lips 1 10, 1'12 are held in position between retainers 106, 106 and end wall 76. These lips,

which are charged with water or some other suitable liquid, are provided for the purpose of wetting the opposed surfaces of strip 72 before advancing between elements 94 and '96 in order to prevent their being scratched. In one form the liquid incorporates a hardening agent, such as sodium sulfate, chrome alum, acrolein, aldehydes such as formaldehyde, and diketones such as ethyl methyl ketone, for the purpose of obviating any possibility of harming the silver halide stratum as it advances. As shown in FIG. 5, initially a leader i109 composed, for example, of a waterproof paper or plastic extends through housing *68. As shown in ifull lines, the rearward end 114 of leader #109 is curled upon itself for convenient storage in the slot between the spaced portions of wall 76. As shown in dotted lines, the rearward end of leader 109 is provided with ctlaps 116 and i118 the inner surfaces of which are provided with a pressure-sensitive adhesive. In practice, the leading end of film 72 is secured by manual pressure between the elements of this biturcated flap so that strip 72 may be advanced through compartment 68 thereafter. Similarly, the forward end 120 of leader I109 is initially curled upon itself in the slot between the spaced portions of wall 77. In storage, slots 80 and 82 are covered by strips 122 and 124 of pressuresensitive adhesive initially adhering to portions of walls 76 and 77 surrounding the slots for the purpose of hermetically sealing the interior of compartment 68 and retaining the Water within lips 1'10 and 1 12.

Bottom wall 74 is provided with an opening 126 in which is secured a relatively flexible membrane 128 capable of transmitting energy from a vibrator 130. Vibrator 130 is removably aflixed to the underf-ace )f lower wall 74 by guides 132.

A pair of sprockets "134 and 136 are provided to advance strip 72 at a predetermined speed through container 68, by virtue of which successive sections of the strip remain within the chamber for a requisite predetermined processing period during which the silver halide emulsion is completely developed and fixed and the antihalation backing dissolved or bleached.

The invention will be further illustrated by the following nonlimiting examples.

EXAMPLE 1 In a specific example of the foregoing process a fine grain, moderately high speed gelatino iodobromide em-ulsion on a transparent support having an antihalation layer is inserted, as shown in FIG. 1, into the open mouth of a container of the type shown in FIG. 1 Which' carries a processing composition. This processing composition is prepared from a Solution A which incorporates the following ingredients:

This Solution A is prepared under a nitrogen atmosphere as follows: The sodium carboxymethyl cellulose is dissolved in the water in a mixer at room temperature. Thereafter, the sodium sulfite, sodium hydroxide, sodium thiosulfate and citric acid are added to the solution. The hydroquinone then is added and the composition mixed for an'hour at approximately room temperature in a nitrogen atmosphere.

To 60' grams of Solution A there .is then added 2 cc. of a fresh 1% aqueous sodium sulfide solution.

After a thorough mixing, there .is added slowly, drop by drop, a Solution B which comprises:

Water cc 2 lead acetate "grams" 0.016 Cadmium acetate do 0.011

The print is inserted through open slit 37 into container '20 until its lower edge contacts lower edge 26 of the con- .tainer. the upper edge of the print protrudes through slot 48. The container is shaken for a moment. After the print has been immersed [for about 9 seconds, it is withdrawn from between the compressed squeegees at the mouth 3f the container, at which time a clear negative may be observed.

EXAMPLE 2 Materials of the type specified in Example 1 are employed in the container of FIGS. 5 and 6 through which a strip of 5 mm. motion picture film, that had been exposed in conventional fashion, is continuously drawn. A succession of clear motion picture frames results.

The proportions of the ingredients of the processing fluid may be varied Within wide limits. However, where the processing period is within the range of from 2 to 50 seconds, practical resultsare achieved where, by total weight of the fluid, the developer ranges from 1 to 8%, the solvent from 0.3 to 10% and the precipitation nuclei from 0.5 to 3%. For most rapid results, the molar concentration of the solvent should be from two to five times the molar concentration of the developer.

The present invention thus provides a single step photographic process in which the active ingredients are so localized and controlled as to provide many of the advantages of a dry process.

Since certain changes may be made in the above product and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

11. A one-step process (for developing and fixing a plurality of interconnected exposed silver halide emulsions to form a plurality of interconnected negative images which comprises introducing said interconnected exposed emulsions at a predetermined speed into a container; continuously advancing said plurality of interconnected emulsions into and through a body of processing fluid confined in a single processing chamber within said container at a predetermined speed sufficient to develop and fix said exposed emulsions, said processing fluid including a suspension of silver precipitating nuclei, said emul- Clip 40 is pivoted into :closed position so that sions being in intimate contact with said body of processing fluid throughout passage therethrough; and continuously withdrawing said developed emulsions at the opposite end of said container through an opening defined by a pair of squeegees, whereby to remove excess processing fluid from said developed emulsions while they are being withdrawn (from said container.

2. A one-step process for devolping and fixing a plurality of interconnected exposed silver halide emulsions to form a plurality of interconnected negative images which comprises continuously introducing said interconnected exposed emulsions at a predetermined speed into one end of a closed container, said container having a single processing chamber provided with a body of processing fiu-id suflicient to process and fix said plurality of emulsions, said processing fluid having a continuous phase including a silver halide developer and a silver halide solvent, 'and a discontinuous phase including si1ver-precipitating nuclei, continuously passing said plurality of emulsions through the processing fliud in said. chamber at a predetermined speed suflicient to develop and fix said exposed emulsions to form a plurality of interconnected 3. The process as defined in claim 2 including the step of removing excess processing fluid from said developed negatives while said negatives are being withdrawn from said container.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Cra'btree: PSA Journal 15, 130436, February 1949.

Gla'fkides: Photographic Chemistry, Fountain Press, London (1957) pp. 101-104.

Miller et al.: American Photography, vol. 42, pp. 76- 79, (1948). v

25 NORMAN G. TORC'H'IN, Primary Examiner.

G. H. BJORGE, J. T. BROWN, Assistant Examiners. 

1. A ONE-STEP PROCESS FOR DEVELOPING AND FIXING A PLURALITY OF INTERCONNECTED EXPOSED SILVER HALIDE EMULSIONS TO FORM A PLURALITY OF INTERCONNECTED NEGATIVE IMAGES WHICH COMPRISES INTRODUCING SAID INTERCONNECTED EXPOSED EMULSIONS AT A PREDETERMINED SPEED INTO A CONTAINER; CONTINUOUSLY ADVANCING SAID PLURALITY OF INTERCONNECTED EMULSIONS INTO AN THROUGH A BODY OF PROCESSING FLUID CONFINED IN A SINGLE PROCESSING CHAMBER WITHIN SAID CONTAINER AT A PREDETERMINED SPEED SUFFICIENT TO DEVELOP AND FIX SAID EXPOSSED EMULSIONS, SAID PROCESSING FLUID INCLUDING A SUSPENSION OF SILVER PRECIPITATING NUCLEI, SAID EMULSIONS BEING IN INTIMATE CONTACT WITH SAID BODY OF PROCESSING FLUID THROUGHOUT PASSAGE THERETHROUGH; AND CONTINUOUSLY WITHDRAWING SAID DEVELOPED EMULSIONS AT THE OPPOSITE END OF SAID CONTAINER THROUGH AN OPENING DEFINED BY A PAIR OF SQUEEGEES, WHEREBY TO REMOVE EXCESS PROCESSING FLUID FROM SAID DEVELOPED EMULSIONS WHILE THEY ARE BEING WITHDRAWN FROM SAID CONTAINER. 